Abstract

Asian seabass (Lates calcarifer) has been designated
as a candidate species for open sea cage culture in
India. A case of vibriosis in Asian seabass reared in
open sea floating cages is reported. Haemorrhage
and ulcer were observed grossly in the diseased
fish. The pathogen, identified as Vibrio alginolyticus
based on biochemical and molecular characterization,
was isolated from liver, gill, kidney, brain and
blood. Histological examination of the diseased fish
showed congestion, haemorrhage and necrosis in
vital organs. The LD50 studies showed that the
organism was virulent to Asian seabass, and the
LD50 value was 103.2 CFU g1 fish.